How Much Fondant Do You Think I Will Need?

Hello fellow CC'rs!!! I am getting ready to make a HUGE quinceanera cake for 200 people. *gasps* I'm trying to figure out how much fondant I will need to cover a four tier cake, measuring 10", 8", 6", 4", with three 10" cakes around it. I make my cakes all 4" tall. Help! Thanks in advance for all your helpfull advice!